This invention relates to conveyors for conveying particulate matter, with particular application to conveyors used to stoke furnaces with combustible particulate matter, such as wood chips, sawdust, pelletized fuel and the like
Stoker-type furnaces in general are exceedingly old, beginning with some of the earliest coal-fired furnaces. The stoker of such a furnace provides a conveyor for moving the solid fuel, in the form of combustible particulate matter, into the furnace for burning. With the energy shortages of the last few years, though, and the realization of the limitations of fossil fuels, there has been a resurgence of interest in wood-fired furnaces, fueled by wood chips, sawdust, pelletized wood fuel and the like. Even users interested in preservation of fossil fuels, though, are also interested in convenience Therefore the resurgence of interest in wood-fired furnaces brought with it a resurgence of interest in stokers.
For example, automatic coal stokers are shown in Crocker, U.S. Pat. No. 2,250,181, Klossner, U.S. Pat. No. 2,333,316 and Campbell, U.S. Pat. No. 2,600,614. In all three of these patents however, all issued between 1940 and 1953, there is very little provision for preventing or reducing the risk of the fuel burning back into the supply and out of control. The David patent, U.S. Pat. No. 4,574,712, shows a stoker with two augers, one positioned above the other and connected by a drop box. Both of the conveyors are directly driven by the same prime mover, though.
This invention relates to improvements to the apparatus described above and to solutions to some of the problems raised or not solved thereby.